1. Field of the Invention
The present invention relates to a method of scaling a partial area of a main picture, by which the partial area of the main picture can be magnified in a manner of scaling the partial area of the picture displayed on a screen like using a virtual magnifier without a separate expensive hardware resource.
2. Discussion of the Related Art
Generally, a digital broadcast receiver is provided with a scaling function for magnifying or reducing a partial area of a picture, which is explained with reference to FIG. 1 as follows. FIG. 1 is a block diagram of a device for scaling a partial area of a picture according to a related art.
Referring to FIG. 1, under the control of a scaler controller 130, a main scaler 110 extracts image data of a partial area to be magnified from full screen image data, which is decoded in a main picture decoder and is inputted via a switch 100, according to an externally inputted magnification command and then magnifies the extracted image data by a full screen size or zooms out only the area to be magnified. In case of zooming-out, the rest area is blacked on the screen, which is shown in FIG. 2.
In FIG. 2A, a main picture 200 of a digital broadcast receiver is shown. In FIG. 2B, a partial picture 210 (width:length=dx:dy) of the main picture 200 is magnified by a full-screen size (width:length=dx′:dy′) of the digital broadcast receiver. In FIG. 2C, a partial picture 210 of the main picture 200, which is magnified like FIG. 2B, is zoomed out by a magnification size (width:length=dx″:dy″) of the digital broadcast receiver. In doing so, the image data of a background picture 220 is processed by black data.
Namely, a general method of selecting a partial area of a main picture and magnifying the selected partial area, as shown in FIG. 2, can be carried out in a following manner. First of all, the area to be magnified is displayed by a screen size or is zoomed out to process the rest area by black.
However, it is difficult to implement the partially magnifying function for the data broadcast image in which OSD (on-screen display) data is included, since the magnifying process is completed prior to the execution of the OSD processing. Moreover, in case that a user intends to view the magnified area and the main picture as well with the main picture intact, it is difficult to implement the magnifying function of high grade. Hence, the demand for an enhanced method of magnifying a partial area is on the increase.